Pet health and activity trackers are bounding on to the market but experts are split on whether they are the cat’s pyjamas or barking up the wrong tree.

As owners monitor their own step count, heart rate, skin temperature and calories burned via wearable tech, a host of companies have developed devices to do the same for pets. According to a report by Future Market Insights, the market for pet fitness trackers is expected to grow to $450m (£333m) by 2035.

Bryan Becker, 52, who lives in Wisconsin, said pet health trackers have been helpful for his two-year-old rescue dog, Kodak, who is anxious, deaf and sight impaired.

“He was always on guard; he would pace and he wouldn’t sleep well,” said Becker. “So we were using [the health tracker] to get a baseline of his activity and his sleeping.”

The device proved useful in finding the right dosage for Kodak’s anti-anxiety medication by providing data on his response. “It was very important to us when we were working with the specialised vet for his anxiety that we still wanted him to be a happy dog that wasn’t being knocked out and sleeping all the time,” said Becker.

“We wanted to make sure that when we were medicating him that he was active in a similar manner to our other dogs who don’t have these issues.”

However, Dr Elizabeth Mullineaux, senior vice-president of the British Veterinary Association suggested the devices could have downsides. “Pet fitness trackers can be a fun tool to gain an insight into your pet’s overall health, but they are ultimately costly and unnecessary accessories with the potential to cause needless worry if the data is over-interpreted,” she said.

“It’s important to remember that there is a lot of key health-related information we can get from day-to-day interactions and observations of our pets, such as their eating, drink, sleeping or scratching habits. Fitness devices should never be used to make a diagnosis or replace veterinary expertise, so if you have any concerns from the data, always contact your vet for advice.”

Perhaps unsurprisingly, companies that produce such trackers say they can be beneficial. “Because pets instinctively hide pain or illness, symptoms often only become observable to humans once a condition is advanced,” said Martin Theißen, CMO of Tractive, a company that produces devices for pets that combine live GPS tracking with health monitoring.

“Our technology establishes a unique baseline for each pet and sends health alerts if vitals deviate, allowing for early veterinary intervention before a situation becomes critical.”

Jonathan Bensamoun, CEO and founder of Fi, which also produces smart pet technology, said: “While too much data might be a valid concern, the right data with the right level of interpretation will inevitably lead to longer, healthier lives for your pets.” He said Fi used AI to interpret the trends and relevance of the data for owners.

He added that while owners’ observations of their pet should be the first layer of information, most people could not spend all day with them, or watch them at night, and humans were generally “pretty weak” at detecting gradual changes.

Proponents believe fitness trackers can also help tackle overweight pets – a problem estimated to affect 50% of dogs – helping owners establish a suitable activity goal and consistently meeting it.

“A significant proportion of money spent at the vet is simply because your dog is too heavy,” said Bensamoun, adding vets could feel uncomfortable raising the issue with owners.

Andrew Nowell, CEO of the pet tracker company Pitpatpet, added that pet fitness trackers had another benefit in capturing data outside of the veterinary clinic. “Many pets present differently at the vet because they are nervous or scared,” he said.

Amanda Boag, the vice-principal for clinical services at the Royal Veterinary College in London said the field of pet health trackers was in its infancy, and it was too early to say how good specific products were.

But she was upbeat about their development, adding the RVC was working on a prototype health tracker with a spinout company.

“I think they have huge potential to improve animal wellbeing, long term, the potential to help with some specific diseases where owners maybe don’t pick up on the signs until it’s quite late, and also then to help improve the communication between the vet and the owner, because that relationship is such a critical relationship for animal health,” she said.